Dräger Regard 3920 - Page 8

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®
3900
Description
3.2 Intended use
The REGARD
®
3900 control units are used with 4–20 mA transmitters to provide
stationary, continuous monitoring of flammable or toxic gases and vapours as well
as oxygen deficiency or surplus. The control unit is primarily intended for use as
part of a gas detection system, but can be used with each remote sensor
transmitter with 4–20 mA source output. This document describes the REGARD
®
3900 series for use as a control unit for a gas detection system. The control unit is
designed for use in private and public facilities as well as in light industry to provide
the
– Output of measured values via the display.
– Output of visual and acoustic alarm messages at the control unit and external
warning devices.
3.3 Limitations on use
The control unit is not intended or permitted for use in areas where flammable or
explosive gas mixtures can develop.
The control unit cannot be used with 3-wire transmitters with a 4–20 mA sink
output.
3.4 Approvals
The REGARD
®
3900 control unit is certified in accordance with Directive
2014/34/EU (ATEX Directive) for operation with approved 4–20 mA transmitters
(EC type examination certificate TÜV 19 ATEX 8400 X).
The REGARD
®
3900 control unit is certified with regard to the measuring function
for explosion protection.
Output modules are not part of the ATEX EC type examination of the REGARD
®
3900. Output modules must not be used for counter measures against explosion
hazards.
Special conditions for safe use according to EC type examination certificate
TÜV 19 ATEX 8400 X
– Only remote sensor transmitters with a valid and suitable ATEX certificate for
safety and measuring performance may be connected to this evaluation system.
These connections can be made via ATEX-certified safety interface barriers.
– Any cable used for the interconnection of remote sensor transmitters must be
selected so that its resistance does not have any adverse effects on the
functional integrity of the controller.
Requirements of EN 60079-29-1
When using a control unit from the REGARD
®
3900 series to detect combustible
gases as protection against explosion hazards, at least one gas alarm relay must
be set to latching. (See EN 60079-29-1 Potentially explosive atmospheres - Gas
detectors - Requirements for the operating behaviour of devices for measuring
combustible gases.)